cycling 'high' to 'low' on comport RTS line
John Shamblin
problem. I don't know if this is a computer software problem or an
interface hardware problem .
I use my Dell Dimension 4100 in digital (ham) radio communication to
activate transmit/receive (push-to-talk switch) of my radio thru the serial
port of the computer.in several digital communication programs.
Pin 7 of DE9 (serial port) is connected thru a diode and a resistor to the
base of a 4N33 opto-isolator, with a grounded source. The drain is
connected to the transceiver push-to-talk switch of the microphone
The resistor is bypassed by an LED that comes on when 'the RTS line is high'
and the transmitter is switched to transmit..
Pin 5 of the DE9 is grounded.
This setup worked well when the OS was Win98SE; but since upgrading to
Win2000 Professional, the LED flashes every two seconds, making the radio
switch back and forth from transmit to receive. The LED cycles the same way
even if disconnected from the radio and sound card in/out circuits even if
the software programs are not loaded
One of the digital programs I am using, WINPSK31v2.12 includes a program
"FixCom.exe" that is supposed to address the problem of holding the comport
RTS line high in Win2000 but does not address the problem of this
spontaneous cycling from high to low. I would appreciate any comments or
suggestions.
John
Guy Harrison
> I am not sure if this the appropriate newsgroup to which to post this
> problem.
Who knows! :-)
> I don't know if this is a computer software problem or an
> interface hardware problem .
Software likely.
> I use my Dell Dimension 4100 in digital (ham) radio communication to
> activate transmit/receive (push-to-talk switch) of my radio thru the
> serial port of the computer.in several digital communication programs.
I know nothing about this...
> Pin 7 of DE9 (serial port) is connected thru a diode and a resistor to
> the
> base of a 4N33 opto-isolator, with a grounded source. The drain is
> connected to the transceiver push-to-talk switch of the microphone
> The resistor is bypassed by an LED that comes on when 'the RTS line is
> high' and the transmitter is switched to transmit..
> Pin 5 of the DE9 is grounded.
>
> This setup worked well when the OS was Win98SE; but since upgrading to
> Win2000 Professional, the LED flashes every two seconds, making the radio
> switch back and forth from transmit to receive. The LED cycles the same
> way even if disconnected from the radio and sound card in/out circuits
> even if the software programs are not loaded
>
> One of the digital programs I am using, WINPSK31v2.12 includes a program
> "FixCom.exe" that is supposed to address the problem of holding the
> comport RTS line high in Win2000 but does not address the problem of this
> spontaneous cycling from high to low. I would appreciate any comments or
> suggestions.
> John
...but I do know the NT (w2k is NT) operating system "abstracts" the
hardware via the HAL (Hardware Abstraction Layer). Using unix talk, the
whole system is in "userland" (not true hence M$ patches but being
theoretical) which means in order to talk to real hardware one must write a
"device driver". In summary, there is not a hope in hell of getting a Win9x
program (under NT) to access hardware. One can run (well/not-to-badly
written) 16bit apps under the NT 16bit subsytem provided they don't access
hardware. One "peek/poke" and you're stuffed: device driver rqd.